1. Field of the Invention
This invention relates to the field of pressure sensors and more particularly to the field of diaphragm-type sensor arrangements for measuring the pressure in slurries and similar flows.
2. Discussion of the Background
Diaphragm-type sensor arrangements are widely used to measure the pressure in fluids flowing through pipes. In a typical arrangement, the pressure sensor is mounted on the main pipe by a stub or connecting line. The pressure of the flow in the main pipe is then transmitted by the connecting line to the sensor where the reading is either viewed directly or sent to a remote, monitoring location.
Commercially available systems normally include a housing with a guard for the sensor wherein the housing includes a chamber isolated from the fluid in the connecting line by a diaphragm or similar member. The chamber typically includes a second fluid such as glycol or mineral oil. As the diaphragm is displaced due to pressure changes in the connecting line, the change is transmitted to the sensor by the second fluid. Such isolation of the sensor from the fluid of the main pipe is particularly desirable if the flow in the main pipe has corrosive or sticky components or if the flow is a slurry of solids suspended in a liquid carrier.
Slurries in particular can present special operating problems. Chief among them is that the solid particles tend to settle out or consolidate in the connecting line and plug it up. As a result, the pressure of the flow in the main line can be incorrectly transferred to the sensor or not transferred to the sensor at all.
In such slurries that tend to plug or clog the connecting line, a purge line is often provided. The purge line is placed in fluid communication with the connecting line and is typically valved. In operation, the valve of the purge line is opened periodically or just before reading the sensor in an effort to flush out any plug or clog in the connecting line. However, this is not always successful in removing the plug or clog as the pressure differential between the flow of the main pipe and the outlet of the purge line may not be sufficient to dislodge and flush the plug or clog from the connecting line.
With this and other problems in mind, the present invention was developed. In it, a diaphragm-type sensor arrangement is provided which includes a reaming member. The reaming member is movable to mechanically clean out the connecting line to breakup or dislodge any partial or complete plugs or clogs. The gauge of the sensor arrangement can then be relied upon to accurately read the flow pressure in the main pipe.